The present invention is directed to door operators for controlling a door and methodology for controlling the door.
The prior art contains at least several patents related to door closers. For example, U.S. Pat. No. 4,973,894 to Johansson describes what the inventor therein characterizes as a method and arrangement for optimizing the operation of a door closer at different phases of opening and closing of the door. In particular, this '894 patent describes that the door closer is provided with a force transmission shaft that turning in accordance with the movements of the door and with a spring element operationally connected thereto. The opening of the door takes place against the force of the spring element. The '894 patent states that at the closing phase of the door the energy of the spring element, exceeding the return force of the spring element needed to accomplish the desired closing movement of the door, is recovered through simultaneous braking of the closing movement of the door for the main part of the closing movement. When the door is only somewhat open any more, preferably under 5. degrees, a final force securing the closing of the door is accomplished by making use of the recovered energy. The '894 patent describes that the door closer is provided with a rotor, a stator and an energy storing device arranged to serve as an electric generator or as an electric motor as required.
However, it is believed that the state of the art has perceived deficiencies.
The present invention overcomes the deficiencies in the prior art, as well as achieves the objectives and advantages set forth herein.